CN212871539U - Marine fiber grating temperature sensor - Google Patents

Marine fiber grating temperature sensor Download PDF

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Publication number
CN212871539U
CN212871539U CN202022238902.2U CN202022238902U CN212871539U CN 212871539 U CN212871539 U CN 212871539U CN 202022238902 U CN202022238902 U CN 202022238902U CN 212871539 U CN212871539 U CN 212871539U
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valve box
pipe
valve
temperature sensor
upper cover
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Expired - Fee Related
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CN202022238902.2U
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Chinese (zh)
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江舒
孟栋成
甘中维
王佳妮
吉海
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Quzhou University
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Quzhou University
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Abstract

The utility model relates to a marine fiber grating temperature sensor, its characterized in that: the FBG, the capillary steel pipe, the thick metal pipe and the adhesive are included; the bare FBG is sleeved with the capillary steel pipe, the optical fibers on two sides of the FBG are sleeved with the thin metal pipes, one end of one thin metal pipe is fixedly connected with one end of the capillary steel pipe, and the capillary steel pipe is suspended in the air; the thick metal pipe is used for cementing two thin metal pipes on the inner cavity of the thick metal pipe through the adhesive; the optical cable is sleeved at two ends of the optical fiber; the adhesive is bonded with the thin metal pipe; a cavity is arranged in the pipe wall of the thick metal pipe; the cavity is filled with mercury; and a liquid inlet is arranged on the outer wall of the metal thick pipe. The utility model discloses a temperature sensor detects the precision height, and detection effect is good, the installation of being convenient for, the maintenance of being convenient for.

Description

Marine fiber grating temperature sensor
Technical Field
The utility model belongs to the technical field of the optical fiber sensor technique and specifically relates to a marine fiber grating temperature sensor is related to.
Background
The application of optical fibers is a major breakthrough in the field of sensors, originating from fiber optic communication technology. In optical communication, it is found that when environmental conditions such as temperature and stress are changed, the intensity, phase, frequency, polarization state, etc. of light waves transmitted through an optical fiber are changed, and the change of the amount of light waves is measured, so that the magnitude of physical quantities such as temperature and stress caused by the change can be known, and an optical fiber sensor can be developed based on these principles.
The optical fiber used by the optical fiber sensor is basically the same as the optical fiber used for common communication, and consists of a fiber core, a cladding and a coating layer. The main component of the fiber core of the optical fiber is silicon dioxide, which contains a very small amount of dopant, generally germanium dioxide, and is used for improving the refractive index of the fiber core, and the weak light guide fiber forming the total internal reflection condition limits light in the fiber core. The diameter of the fiber core is 5-50 μm, wherein the diameter of the single mode fiber is 9 μm, and the diameter of the multimode fiber is 50 μm. The cladding was also silica based and had a diameter of 125 μm. The coating layer is generally made of high polymer materials such as epoxy resin, silicon rubber and the like, has the outer diameter of 250 mu m, and is used for enhancing the flexibility, mechanical strength and aging resistance of the optical fiber. Some types of optical fiber sensors require some processing on common optical fibers due to different use occasions, so that the optical fiber sensors are more sensitive to specific signals.
Fiber optic sensors can be generally classified into two types, extrinsic and intrinsic, depending on whether the measured signal is modulated or not. The optical fiber in the extrinsic optical fiber sensor only plays a role in signal transmission, the other detection device modulates carrier light to obtain signals, and the detection principle and the signals capable of being measured are simpler. Because the optical fiber in the extrinsic optical fiber sensor only plays a role of signal transmission, which is equivalent to the role of a conducting wire in a common sensor, the extrinsic optical fiber sensor cannot be called as an optical fiber sensor in the application of the fiber grating sensing technology in structural health monitoring in a strict sense. The intrinsic optical fiber sensor not only transmits signals, but also plays a sensing role, namely, the intrinsic optical fiber sensor modulates the light to be measured into the change of the intensity, the phase, the polarization or the wavelength of the light through the photosensitive effect, the photoelastic effect, the birefringence effect, the Faraday effect, the fluorescence effect and the like of the optical fiber. The intrinsic fiber sensor is also called a functional fiber sensor or an internal modulation fiber sensor, or an all-fiber sensor. The so-called fibre optic sensors are all intrinsic fibre optic sensors. The optical fiber sensors can be classified into point sensors, quasi-distributed sensors, and distributed sensors according to the spatial distribution of the measurement. The latter two sensors are the functions peculiar to the optical fiber sensor, and can measure the parameter distribution of space multiple points or infinite multiple degrees of freedom on a structure by using one optical fiber, which can be said to be the fundamental change of the sensor technology.
With the development of world trade and economy, the international shipping industry plays a vital role, the development of global economy integration does not leave the support of the shipping industry, and meanwhile, the explosive development of the shipping industry is promoted. The safety performance of ships, which are important vehicles in the shipping industry, is also a focus of attention. The strength of the hull structure is one of important factors determining the safety performance of the ship, relevant specifications and standards are established in the design and construction process of the ship by the classification society, and relevant requirements and plans are provided for the construction process and the maintenance of the ship, so that the strength of the hull structure can bear the damage of environmental loads. However, when a ship is sailing in a marine environment, the structure is subjected to external loads with strong randomness, and it is difficult to accurately predict these random factors during the design and construction process. Therefore, ship structure stress monitoring and evaluating systems are proposed to ensure the safety of ships in the working process.
The ship structure stress monitoring and evaluating system is characterized in that a sensor is arranged in a ship body structure, and acquired data are analyzed and processed through a computer so as to achieve the purpose of structure safety monitoring. The system can monitor the key structure of the ship body in real time, evaluate the structural strength of the ship body in the current environment through data acquired by the sensor, provide guiding experience for ship design, display latest real and reliable data for decision makers, ensure the safety of ship personnel and articles, improve the risk prediction capability of the ship, enhance the safety performance of the ship and provide scientific basis for guaranteeing the healthy navigation of the ship. The research on the ship structure health monitoring technology in China is gradually developing, and the exploration of the field is more and more emphasized. In order to further improve the applicability and reliability of the ship structure stress monitoring and evaluating system in practical application, the ship structure stress monitoring and evaluating system needs to be deeply researched and perfected. By optimizing and improving various functions of the ship structure stress monitoring and evaluating system, the feasibility and the applicability of the system in practical application are improved. Through the performance test of the ship monitoring fiber grating sensor, the fiber grating sensor type suitable for ship structure monitoring can be selected. Through the research on the fault diagnosis of the marine fiber grating sensor, the system failure caused by the sensor fault can be avoided or reduced. Through the establishment of a ship structure stress monitoring and evaluating system model machine and the verification of various functions of the system, the system model machine is further optimized and perfected, so that the system can finally meet various requirements in engineering practical application.
The fiber grating strain sensor has the advantages of magnetic interference resistance, corrosion resistance, light weight, small size and the like, and plays a great role in various structural health monitoring systems. For the ship structure health monitoring, on one hand, the stress condition, fatigue damage and the like of key parts of a ship body can be monitored in real time in the ship navigation process, and early warning can be given out when a dangerous condition is met, so that the safe navigation of the ship is ensured; on the other hand, the design of the large ship is continuously optimized by using the acquired detection data, the structure is improved, the shipbuilding capacity is improved, and the ship is safer and more reliable. It cannot be seen that the accuracy of the fiber grating strain sensor measurements is critical.
The temperature is one of basic physical quantities given by international units, is a main parameter which needs to be measured and controlled frequently in industrial and agricultural production and scientific experiments, and is also an important physical quantity closely related to daily life of people. Before, the electrical temperature sensors which are commonly used are mainly thermocouple temperature sensors and thermistor temperature sensors. The thermocouple is mainly used for measuring temperature difference, in order to obtain a correct temperature value, a reference temperature is needed to correct a contact point, an output signal is relatively small, and therefore the measurement accuracy is low if the measurement mode is not noticed near normal temperature. The thermistor temperature sensor has high response speed, strong resistance variation capability along with temperature, but poor long-term stability.
Moreover, the conventional electric temperature sensor is easily interfered by electromagnetic radiation, has low precision, poor long-term stability and short signal transmission distance, and cannot meet the working requirement in severe working environments such as strong electromagnetic radiation and the like. Compared with the traditional sensor, the optical fiber temperature sensor has the advantages of high sensitivity, small size, corrosion resistance, electromagnetic radiation resistance, bendable light path, convenience in remote measurement and the like. However, in practical applications, the optical fiber temperature sensor based on intensity modulation is susceptible to power variation of a light source, line loss and the like, and thus has poor long-term measurement stability. The optical fiber temperature sensor based on the optical fiber grating technology adopts the wavelength coding technology, eliminates the influence of light source power fluctuation and system loss, is suitable for long-term monitoring and a temperature sensing system consisting of a plurality of optical fiber gratings, and can realize quasi-distributed measurement by adopting one optical cable.
Temperature is a factor directly influencing the wavelength change of the fiber grating, and people often directly apply the bare fiber grating as a temperature sensor. As with the fiber grating strain sensor, the fiber grating temperature sensor also needs to be packaged, the main function of the packaging technology is protection and sensitivity enhancement, people hope that the fiber grating has stronger mechanical strength and longer service life, and meanwhile hope that the response sensitivity of the fiber grating to the temperature can be improved through the appropriate packaging technology in the fiber sensing; in order to improve the heat conduction efficiency, the temperature sensor of the existing fiber grating sensor infuses mercury into a metal thick tube; however, in such a way, the valves at the infusion port and the liquid discharge port frequently fail due to the influence of moisture, so that mercury leaks out to pollute the environment; in addition, when the temperature sensor of the fiber grating sensor at the present stage is used on a ship body, the temperature sensor is usually installed in a narrow area, and needs to be installed at a fixed position when being applied, and is inconvenient to use due to problems of space and the like if the temperature sensor needs to be moved and maintained and needs to be disassembled.
SUMMERY OF THE UTILITY MODEL
Not enough to prior art exists, the utility model aims to provide a marine fiber grating temperature sensor.
The technical scheme of the utility model is realized like this: the marine fiber grating temperature sensor is characterized in that: the FBG, the capillary steel pipe, the thick metal pipe and the adhesive are included; the bare FBG is sleeved with the capillary steel pipe, the optical fibers on two sides of the FBG are sleeved with the thin metal pipes, one end of one thin metal pipe is fixedly connected with one end of the capillary steel pipe, and the capillary steel pipe is suspended in the air; the thick metal pipe is used for cementing two thin metal pipes on the inner cavity of the thick metal pipe through the adhesive; the optical cable is sleeved at two ends of the optical fiber; the adhesive is bonded with the thin metal pipe; a cavity is arranged in the pipe wall of the thick metal pipe; the cavity is filled with mercury; a liquid inlet is arranged on the outer wall of the metal thick pipe; and a single valve for preventing mercury from leaking is arranged on the liquid inlet.
Preferably: the single valve comprises a silica gel valve body, a valve box upper cover and a valve box lower cover, wherein the valve box upper cover is provided with an air hole, and the valve box lower cover is provided with an air inlet pin; the silica gel valve body include outer loop and inner ring, the inside of inner ring is confined valve block, connect through the flexure strip between inner ring and the outer loop, the outer loop is fixed between valve box upper cover and the valve box lower cover, the inner ring is unsettled state between valve box upper cover and the valve box lower cover.
Preferably: the lower cover of the valve box is provided with a bearing ring, the lower surface of the outer ring is arranged on the bearing ring, and the upper surface of the outer ring is pressed by the upper cover of the valve box; the number of the elastic pieces is at least three, and the elastic pieces are evenly distributed on the circumference; and an anti-tripping device is arranged between the valve box upper cover and the valve box lower cover.
Preferably: the inner surface of the upper cover of the valve box is an inner spherical surface, and the upper surface of the inner ring in a lifting state is tightly attached to the inner spherical surface.
Compared with the prior art, the utility model discloses the beneficial effect who brings does:
1. mercury is filled in the inner cavity of the thick metal tube of the temperature sensor for packaging the fiber bragg grating sensor, and is a good heat conducting agent, so that the detection precision and the detection effect of the sensor are improved;
2. through be provided with the check valve on the inlet, because the silica gel valve body includes outer loop and inner ring, inner ring's inside is confined valve block, connect through the flexure strip between inner ring and the outer loop, the outer loop is fixed between valve box upper cover and the valve box lower cover, the inner ring is unsettled state between valve box upper cover and the valve box lower cover, can help avoiding vapor or liquid that gas brought to glue the silica gel valve body, and effectively avoid the inboard interference of facing the normal action of silica gel valve body in the cavity, promote the normal performance efficiency of check valve function by a wide margin, the inside liquid of control container seals or the circulation state, moreover, the steam generator is simple in structure, reliable functions.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
FIG. 1 is a schematic structural view of an embodiment of the present invention;
FIG. 2 is a cross-sectional view of the check valve;
FIG. 3 is a schematic structural view of a silica gel valve body;
FIG. 4 is a schematic structural view of the upper cover of the valve box;
fig. 5 is a schematic structural diagram of the lower cover of the valve body.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
Example 1
As shown in fig. 1, the utility model discloses a fiber grating temperature sensor for ships, which comprises an optical cable 1, two metal thin pipes 2, a FBG3, a capillary steel pipe 4, a metal thick pipe 5 and an adhesive 6; the capillary steel tube 4 is sleeved outside the bare FBG3, the optical fibers on two sides of the FBG3 are sleeved with the thin metal tubes 2, one end of one thin metal tube 2 is fixedly connected with one end of the capillary steel tube 4, and the capillary steel tube 4 is suspended in the air; the thick metal pipe 5 is characterized in that two thin metal pipes 2 are glued to the inner cavity of the thick metal pipe 5 through the adhesive 6; the optical cable 1 is sleeved at two ends of the optical fiber; which is bonded to the thin metal tube 2 by said adhesive 6.
The temperature sensor of the fiber grating strain sensor has the advantages that: the inner cavity of the metal thick tube of the temperature sensor for packaging the fiber bragg grating sensor is filled with mercury, and the mercury is a good heat conducting agent, so that the temperature transfer effect is enhanced, and the detection precision and the detection effect of the sensor are improved.
In addition, the capillary steel pipe is suspended through the thin metal pipe, the FBG in the capillary steel pipe is also suspended, the FBG is prevented from shaking when the FBG is used, the FBG damage is avoided, and the detection precision and the service life of the sensor are improved.
Example 2, unlike example 1
As shown in fig. 2 to 5, in the embodiment of the present invention, a cavity 51 is disposed in a tube wall of the thick metal tube 5; the cavity 51 is filled with mercury; a liquid inlet is arranged on the outer wall of the metal thick pipe 5; and a single valve 7 for preventing mercury from leaking is arranged on the liquid inlet.
In the specific embodiment of the present invention, the one-way valve 7 includes a silica gel valve body 71, a valve box upper cover 72 and a valve box lower cover 73, the valve box upper cover 72 is provided with an air hole 721, and the valve box lower cover 73 is provided with an air inlet pin 74; the silica gel valve body 71 comprises an outer ring 711 and an inner ring 712, a closed valve plate is arranged inside the inner ring 712, the inner ring 712 is connected with the outer ring 711 through an elastic sheet 75, the outer ring 711 is fixed between the valve box upper cover 72 and the valve box lower cover 73, and the inner ring 712 is suspended between the valve box upper cover 72 and the valve box lower cover 73.
In the specific embodiment of the present invention, the valve box lower cover 73 is provided with a supporting ring 76, the lower surface of the outer ring 711 is disposed on the supporting ring 76, and the upper surface of the outer ring 711 is pressed by the valve box upper cover 72; at least three elastic pieces 76 are arranged, and the circumferences of the elastic pieces 75 are evenly distributed; an anti-tripping device 78 is arranged between the valve box upper cover 72 and the valve box lower cover 73.
In the present embodiment, the inner surface of the valve box upper cover 72 is an inner spherical surface, and the upper surface of the inner ring 712 in the raised state is attached to the inner spherical surface.
Through adopting above-mentioned technical scheme, through be provided with the check valve on the inlet, because the silica gel valve body includes outer loop and inner ring, inner ring's inside is confined valve block, connect through the flexure strip between inner ring and the outer loop, the outer loop is fixed between valve box upper cover and the valve box lower cover, the inner ring is unsettled state between valve box upper cover and valve box lower cover, can help avoiding gaseous vapor or the liquid that takes in to glue the silica gel valve body, and effectively avoid the inboard interference of facing the normal action of silica gel valve body of cavity, promote the normal performance efficiency of check valve function by a wide margin, the inside liquid of control vessel seals or the circulation state, moreover, the steam generator is simple in structure, and reliable functions.
Wherein, the silica gel valve body is internally provided with three elastic sheets which are evenly distributed and connected with the outer ring and the inner ring of the valve body, the inner ring 6 is always positioned in the middle of the cavity, is not contacted with the inner side surface of the cavity, can only keep parallel up-and-down movement, is not interfered by the friction of the inner side wall of the cavity, effectively locks air and plays a role in leakage prevention.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (4)

1. The marine fiber grating temperature sensor is characterized in that: the FBG, the capillary steel pipe, the thick metal pipe and the adhesive are included; the bare FBG is sleeved with the capillary steel pipe, the optical fibers on two sides of the FBG are sleeved with the thin metal pipes, one end of one thin metal pipe is fixedly connected with one end of the capillary steel pipe, and the capillary steel pipe is suspended in the air; the thick metal pipe is used for cementing two thin metal pipes on the inner cavity of the thick metal pipe through the adhesive; the optical cable is sleeved at two ends of the optical fiber; the adhesive is bonded with the thin metal pipe; a cavity is arranged in the pipe wall of the thick metal pipe; the cavity is filled with mercury; a liquid inlet is arranged on the outer wall of the metal thick pipe;
and a single valve for preventing mercury from leaking is arranged on the liquid inlet.
2. The marine fiber grating temperature sensor of claim 1, wherein: the single valve comprises a silica gel valve body, a valve box upper cover and a valve box lower cover, wherein the valve box upper cover is provided with an air hole, and the valve box lower cover is provided with an air inlet pin; the silica gel valve body include outer loop and inner ring, the inside of inner ring is confined valve block, connect through the flexure strip between inner ring and the outer loop, the outer loop is fixed between valve box upper cover and the valve box lower cover, the inner ring is unsettled state between valve box upper cover and the valve box lower cover.
3. The marine fiber grating temperature sensor of claim 2, wherein: the lower cover of the valve box is provided with a bearing ring, the lower surface of the outer ring is arranged on the bearing ring, and the upper surface of the outer ring is pressed by the upper cover of the valve box; the number of the elastic pieces is at least three, and the elastic pieces are evenly distributed on the circumference; and an anti-tripping device is arranged between the valve box upper cover and the valve box lower cover.
4. The marine fiber grating temperature sensor of claim 3, wherein: the inner surface of the upper cover of the valve box is an inner spherical surface, and the upper surface of the inner ring in a lifting state is tightly attached to the inner spherical surface.
CN202022238902.2U 2020-10-10 2020-10-10 Marine fiber grating temperature sensor Expired - Fee Related CN212871539U (en)

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Application Number Priority Date Filing Date Title
CN202022238902.2U CN212871539U (en) 2020-10-10 2020-10-10 Marine fiber grating temperature sensor

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Application Number Priority Date Filing Date Title
CN202022238902.2U CN212871539U (en) 2020-10-10 2020-10-10 Marine fiber grating temperature sensor

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112254837A (en) * 2020-10-10 2021-01-22 衢州学院 Marine fiber grating temperature sensor and use method thereof
CN114739434A (en) * 2022-04-27 2022-07-12 兰州大学 Flexible packaging method for distributed optical fiber sensing device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112254837A (en) * 2020-10-10 2021-01-22 衢州学院 Marine fiber grating temperature sensor and use method thereof
CN114739434A (en) * 2022-04-27 2022-07-12 兰州大学 Flexible packaging method for distributed optical fiber sensing device

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